My browser automatically launches five Web sites: two blogs, two social networks, and my Google RSS reader. So feel free to consider me a poster child for a new study that measures the popularity (read: power) of social media among the U.S. female Internet population.

The takeaway, of course, is if women are the market for your product or service, then ignoring social media tools would be as senseless as sending your favorite cookie recipe to Hillary Clinton. That's because of the 79 million U.S. women online, 42 million women are actively engaging in some form of social media, according to the "2009 Social Media Study" (PDF) from BlogHer and iVillage (two women-focused resources), and Compass Partners (a marketing consultancy).

The question becomes, where are those 42 million ladies spending their time within the social media space, and why exactly are they using it? (OK, OK, that was really two questions.)

In terms of where, social networks, such as Facebook, was cited as the most popular destination, with three-quarters (31.5 million) participating, followed by 55% who use blogs (for 54% of that 55%, "use" means "read" as opposed to post to or publish). In addition, 40% go to message boards and forums, and 16% update their statuses on sites like Twitter.

For the most part, the study focuses on social networks vs. blogging. Interestingly, it determined that women who use blogs were more likely to use social networks than the other way around (80% vs. less than two-thirds, respectively). In terms of why they're using social media, fun reigns supreme for both the blog- and social network-engaged, though they're almost twice as likely to turn to blogs to obtain information (such as product and pricing details), seek advice and recommendations, and stay informed about specific topics (the biggies include technology/gadgets, social activism, green, politics/news, business/career/personal finance, travel, and pregnancy/baby).

Women also report they are significantly more likely to make a purchase decision based on customer experiences reported on blogs, according to the survey.

"Many blogs set up by businesses, whether small or large, are initially created to provide another avenue in which the company can connect with existing and new users," said Blogher co-founder Jory Des Jardins, when we spoke in October (here's the post, which includes what makes for a good small-business blog). "By creating a blog, you are creating an open dialogue with an audience that is able to receive and exchange information with your company. This dialogue can be extremely useful for the users as they can provide feedback on products and services. For the company, blogs provide direct and targeted information to the users in an immediate and timely manner."

Whether you can expect a huge uptick in sales, though, is debatable. Last week bMighty publisher Fredric Paul blogged about a study from research house Knowledge Networks that found "less than 5% of social media users regularly turn to these sites for guidance on purchase decisions in any of nine product/service categories. In addition, only 16% of social media users say they are more likely to buy from companies that advertise on social sites."

In a less dramatic difference, research from Warrillow & Co. showed that 40% of small businesses read blogs for business purposes.

True, neither of those two studies are an apples-to-apples comparison given the 2009 Social Media Study looks only at women. But even if the latter's results seem a bit slanted, I think the takeaway up top still holds true: If women are the market for your product or service, then ignoring social media doesn't make sense.

If you haven't explored social media yet, tell me: What's holding you back?